A McDonnell Douglas DC-10-10, N450AX (Tanker 910), impacted trees with the left wing during a fire suppression flight in support of the White Fire about 12 miles southwest of Tehachapi, California. The airplane was owned by BC Aircraft Leasing LLC, and leased to 10 Tanker Air Carrier, LLC. The California Department of Forestry and Fire Prevention (Cal Fire) was operating the airplane as a public use flight. The captain, first officer (FO), and flight engineer (FE), were not injured. The airplane was substantially damaged. The airplane departed Victorville-Southern California Logistics Airport, California, at 16:57. According to Cal Fire personnel, the flight crew was preparing to jettison a load of retardant. While turning on final for the drop, the left wing impacted several trees. The flight crew climbed the airplane to 11,000 feet where they jettisoned the fire retardant. Then, they landed uneventfully at their departure airport at 17:48. Thirteen impacted trees were identified by Cal Fire personnel. The first identified tree that sustained impact was 45 feet tall at a base elevation of 7,786 feet mean sea level (msl). PROBABLE CAUSE: “The captain’s failure to maintain clearance from trees.”